P(x)= x^5-4x^4+3x^3+2x-6
use descartes rule of signs to analyze the zeros

notice where how many "yes" sign change happen in the positive "x"
and the on the negative "-x"

for the P(x) is 3 changes, thus
so is either 3 real positive ones, or 3-2 = 1 real positive one

P(-x) gives no sign changes, so there are 0 negative ones

the polynomial has a degree of 5, thus 5 roots
if it has 3 real positive ones, then it has 2 complex ones
the complex ones pick up the slack per se

if it has 1 real positive one, then it has 4 complex ones

bear in mind complex ones always come in pairs